An internal combustion engine may be selectively stopped and started while a vehicle is activated. It may be desirable to know engine position when the engine is restarted so that fuel may be delivered to engine cylinders in a timely manner so that engine cylinders do not receive multiple fuel injections when only one fuel injection is desired. Further, by injecting fuel to engine cylinders at known engine positions, engine emissions may be reduced and engine starting consistency may be provided. However, if a vehicle is deactivated it may not be assured that the engine starts from an engine position last determined by the engine's controller while the engine was being stopped. For example, the engine position sensors may not be sensitive to zero engine speed. Consequently, the last sensed engine position may not be the engine's stopped position. Further, the engine's stopping position may be changed from a first stop position if the vehicle includes a clutch to engage the engine to the vehicle's wheels and vehicle brakes are released while the vehicle is parked on a hill. For these reasons, it may be desirable to rotate the engine and establish the engine's position before supplying spark and fuel to the engine. By rotating an engine that was stopped, engine position may be established before spark and fuel are supplied to the engine so that fuel and spark may be timely supplied to the engine. However, the engine may have to be rotated at cranking speed for a longer time than is desired if engine position cannot be established from engine position sensor information in a timely manner. As a result, it may take more than a desired amount of electrical energy to rotate the engine before the engine is started. Further, engine starting time may be increased.
The inventors herein have recognized the above-mentioned issues and have developed an engine operating method, comprising: after stopping an engine, rotating the engine via an electric machine to a first position and then stopping engine rotation in response to activating a vehicle and the vehicle being within a predetermined distance of a destination.
By rotating an engine via an electric machine after stopping the engine, it may be possible to determine engine position in case the engine is started during a vehicle activation period. The vehicle activation period may be a time from a time an operator enters a vehicle until the operator exits the vehicle. The vehicle may be propelled via an electric machine or an engine during the vehicle activation period. The engine may be rotated to a first position via an electric machine where engine position may be determined if the vehicle is traveling to a destination of the vehicle that is in range of the vehicle when the vehicle is propelled solely via an electric machine using energy stored in an electric storage device via a stationary power grid and one charging cycle. The engine may be rotated to a second position via the electric machine if the vehicle is traveling to a destination that is beyond the range the vehicle may travel when propelled solely via the electric machine using energy stored in an electric storage device via a stationary power grid and one charging cycle. Rotating the engine to the second position may reduce engine starting time while rotating the engine to the first position may reduce an amount of electrical energy consumed to rotate the engine via the electric machine.
The present description may provide several advantages. For example, the approach may reduce engine starting time. Further, the approach may reduce electrical energy consumption for short trips. Further still, the approach may provide quicker starting as compared to if the engine is left at a random engine stop position when engine starting may not be expected.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.